Having a thick head like a club (the weapon).

A person's head shaped like a bullet. / A stupidly stubborn person.

plural of bullet-head

A South American duck of freshwater habitats, Heteronetta atricapilla, known for laying its eggs in the nests of other ducks.

plural of black-headed duck

(nautical) The distance to windward traversed by a vessel while tacking.

(idiomatic) Of an animal: to cost more to feed than it is worth.

Alternative spelling of arrowhead

plural of arrow-head

(informal, figuratively) Very easily.